Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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PP AR a onists for the treatment of HCV infection
The present invention concerns methods and compositions useful in the
therapeutic treatment of mammals, especially humans. In particular, the
invention
concerns methods and compositions for treatment or prevention of infection by
the
hepatitis C virus (HCV).
HCV is a major human pathogen, infecting about 3 percent of the world's
population, and is a major cause of liver disease. A striking feature of HCV
infection is
the tendency towards a chronic status leading to liver diseases such as
chronic
hepatitis, cirrhosis and hepatocellular carcinoma. HCV infection is also
implicated in
mixed cryoglobulinemia, a B-lymphocyte proliferative disorder.
A major obstacle in understanding the mechanism of HCV infection and in the
design and testing of appropriate therapies is the lack of knowledge of the
HCV
cellular receptors and the mechanisms by which they mediate viral attachment
and
entry to cells. At least three dii~erent receptors have been implicated,
namely the low
density lipoprotein (LDL) receptor (Agnello et al, PNAS, 1999, 96, 12766-71);
the
CD81 receptor (Pileri et al, Science, 1998, 282, 938-41); and the scavenger
receptor
type B class I (SRB 1) (WO 03/040726, Scarselli et al, EMBO, 2002, 12, 58017-
25
and Bartosch et al, J. Biol. Chem., 2003, 278, 41624-30).
Peroxisome proliferator receptors (PPARs) form part of the nuclear receptor
superfamily and are in involved in the control of lipid metabolism. They exist
as oc, (3, y
and ~ subtypes (for a review, see Desvergne and Wahli, Endocrine Reviews,
1999, 20,
649-88). PPAR activation has been linked to diverse phenomena such as fatty
acid
metabolism, inflammatory responses, atherosclerosis and control of the cell
cycle.
However, there has hitherto been no disclosure of a link between PPAR activity
and
HCV infection.
According to the present invention, there is provided the use of a PPARoc
agonist for the manufacture of a medicament for treatment or prevention of HCV
infection in a mammal. °
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There is further provided a method of treating or preventing HCV infection in
a
mammalian subject comprising administration to that subject of a
therapeutically
effective amount of a PPARa agonist. Typically, the mammalian subject is
human.
Figure 1 shows the numbers of copies of HCV RNA detected when cultured
human hepatocytes were incubated with serum from an HCV-infected patient in
the
presence and absence of fenofibric acid.
It is believed that PPARa agonism has the effect of inhibiting entry of HCV to
hepatocytes, possibly through a reduction of the expression and/or cell
surface display
of SRB 1. Such effect is useful both in preventing infection by HCV in the
first place
and in arresting the progress of an existing infection by preventing further
cells from
becoming infected. Thus, in accordance with the invention, the PPARoc agonist
may
usefully be administered to subjects at risk of contracting HCV infection
(prophylaxis)
or t~ subjects who have already contracted HCV infection (active treatment).
According to a further aspect of the invention, there is provided a method of
inhibiting entry of HCV to a cell comprising contacting said cell with a PPARa
agonist. Preferably the cell is a hepatocyte.
In principle, any compound known or discovered to have PPARa agonist
activity may be used in the invention, but compounds suitable for oral
administration
are preferred. Compounds having PPARa agonist activity may be identified using
published assay methods such as the cell-based transactivation assay described
in
Berger et al, .LBiol.Chem., 1999, 274, 6718-25. Suitable compounds include
those
which are selective PPARcc agonists and those which combine activity at the
alpha
receptor with activity at one or more of the other subtypes, e.g. PPARoc/y
dual
agonists. Known selective PPARa agonists include fenofibrate, beclofibrate,
bezafibrate, ciprofibrate, clofibrate, etofibrate, other fibric acid
derivatives,
gemcarbene, gemfibrozil, GW 7647, BM 170744, LY 518674, AtromidTM, LopidTM
and TricorTM, as well as compounds disclosed in Adams et al Bioorg. Med. Chem.
Lett., 2003, 13, 3185-90. Examples of PPARa/y dual agonists include include
KRP-
297 (MK-0767), muraglitazar (BMS-298585), farglitazar, ragaglitazar,
tesaglitazar
(AZ-242), JT-501, GW-2570, GI-262579, CLX-0940, GW-1536, GW-1929, GW-
2433, L-796449, LR-90, SB-219994, LY-578, LY-4655608, LSN-862, LY-510929
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and LY-929, as well as compounds disclosed in Desai et al Bioo~g. Mec~' Chem.
Lett.,
2003, 13, 3541-4 and in Desai et al Bioorg. Med. Chem. Lett., 2003, 13, 2795.
Further disclosure of selective PPARoc agonists or PPARa/y dual agonists
appears in
WO 97/28115, WO 00/78312, WO 00/78313, WO 00/196321, WO 00/181327, WO
00/134148, WO 02!064094, WO 02/060434, WO 02/26729, WO 01/60807,
EP1194147, EP1194146, WO 03/066581 and WO 03/075911. .
Preferred compounds for use in the invention include fenofibrate, bezafibrate,
ciprofibrate, gemfibrozil and MK-0767.
The PPARa agonist may be administered alone or in combination with one or
more additional therapeutic agents known to be useful in the treatment or
prevention of
HCV infection or the symptoms thereof. Examples of such additional therapeutic
agents include interferon-a, pegylated interferon-oc, ribavirin, HCV NS3
protease
inhibitors, HCV polymerase inhibitors, anti-HCV antibodies and HCV vaccines.
As
used herein, the expression "in combination with" requires that
therapeutically effective
amounts of both the PPARa agonist and the additional therapeutic agent are
administered to the subject, but places no restriction on the manner in which
this is
achieved. Thus, the two species may be combined in a single dosage form for
simultaneous administration to the subject, or may be provided in separate
dosage
forms for simultaneous or sequential administration to the subject. Sequential
administration may be close in time or remote in time, e.g. one species
administered in
the morning and the other in the evening. The separate species may be
administered at
the same frequency or at different frequencies, e.g. one species once a day
and the
other two or more times a day. The separate species may be administered by the
same
route or by different routes, e.g. one species orally and the other
parenterally, although
oral administration of both species is preferred, where possible. When the
additional
therapeutic agent is a vaccine or antibody, it will typically be administered
parenterally
and separately from the PPARa, agonist.
In a further aspect, the invention provides a pharmaceutical composition or
kit
comprising, in the same or separate pharmaceutically acceptable carriers, a
PPARoc
~ agonist and one or more therapeutic agents selected from interferon-oc,
pegylated
interferon-oc, ribavirin, HCV NS3 protease inhibitors, HCV polymerase
inhibitors, anti-
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HCV antibodies and HCV vaccines. Kits comprising separately-formulated
therapeutic
agents will typically comprise instructions for the separate administration of
the
therapeutic agents.
The PPARoc agonists and optional additional therapeutic agents) are typically
used in the form of pharmaceutical compositions comprising the relevant active
ingredients) and a pharmaceutically acceptable carrier. Where the active.
ingredient
comprises an acidic or basic group, said ingredient may be in the form of the
free acid
or base or in the form a pharmaceutically acceptable salt. Preferably the
pharmaceutical compositions are in unit dosage forms such as tablets, pills,
capsules,
powders, granules, sterile parenteral solutions or suspensions, metered
aerosol or liquid
sprays, drops, ampoules, transdermal patches, auto-injector devices or
suppositories;
for oral, parenteral, intranasal, sublingual or rectal administration, or for
administration
by inhalation or insufllation. The principal active ingredient typically is
mixed with a
pharmaceutical carrier, e.g. conventional tableting ingredients such as corn
starch,
lactose, sucrose, sorbitol, talc, stearic acid, magnesium stearate and
dicalcium
phosphate, or gums, dispersing agents, suspending agents or surfactants such
as
sorbitan monooleate and polyethylene glycol, and other pharmaceutical
diluents, e.g.
sterile water, to form a homogeneous preformulation composition containing a
compound of the present invention, or a pharmaceutically acceptable salt
thereof.
When referring to these preformulation compositions as homogeneous, it is
meant that
the active ingredient is dispersed evenly throughout the composition so that
the
composition may be readily subdivided into equally ei~ective unit dosage forms
such as
tablets, pills and capsules. This preformulation composition is then
subdivided into unit
dosage forms of the type described above containing from 0.1 to about 500 mg
of the
active ingredient of the present invention. Typical unit dosage forms contain
from 1 to
100 mg, for example 1, 2, 5, 10, 25, 50 or 100 mg, of the active ingredient.
Tablets or
pills of the composition can be coated or otherwise compounded to provide a
dosage
form affording the advantage of prolonged action. For example, the tablet or
pill can
comprise an inner dosage and an outer dosage component, the latter being in
the form
of an envelope over the former. The two components can be separated by an
enteric
layer which serves to resist disintegration in the stomach and permits the
inner
component to pass intact into the duodenum or to be delayed in release. A
variety of
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materials can be used for such enteric layers or coatings, such materials
including a
number of polymeric acids and mixtures of polymeric acids with such materials
as
shellac, cetyl alcohol and cellulose acetate.
The liquid forms in which the compositions usefixl in the present invention
may
be incorporated for administration orally or by injection include aqueous
solutions,
liquid- or gel-filled capsules, suitably flavoured syrups, aqueous or oil
suspensions, and
flavoured emulsions with edible oils such as cottonseed oil, sesame oil or
coconut oil,
as well as elixirs and similar pharmaceutical vehicles. Suitable dispersing or
suspending
agents for aqueous suspensions include synthetic and natural gums such as
tragacanth,
acacia, alginate, dextran, sodium carboxymethylcellulose, methylcellulose,
polyethylene glycol), poly(vinylpyrrolidone) or gelatin.
For treating or preventing HCV infection, a suitable dosage levels of the
PPARa agonist are similar with published values for the compounds concerned
when
used for other therapeutic purposes (e.g. control of lipid levels), or may be
determined
by methods known to those skilled in the art. Typical levels are in the range
of about
0.01 to 250 mg/kg per day, preferably about 0.01 to 100 mg/kg per day, and
more
preferably about 0.05 to 50 mg/kg of body weight per day, of the active
compound.
Any suitable dosing regimen may be used, e.g. 1-4 times daily.
A suitable dose of fenofibrate is 100 - 200mg per adult person daily.
EXAMPLES
Example 1. Inhibition of HCV infection of cultured Human Hepatoc. es by
Fenofibric Acid.
Isolated human hepatocytes from surgical liver resection were seeded in 24
well
microplates at the density of 3x105 cells/well. Cells were allowed to attach
and recover
24 hours and then medium was replaced with a fresh one containing diiTerent
concentrations of fenofibric acid (SOp,M and SOO~,M). Hepatocytes were
incubated 24
hours with the indicated amounts of fenofibric acid, then medium was replaced
with
fresh one containing the same amounts of fenofibric acid and a fixed amount
(100p,1) of
an infectious human serum from a patient chronically infected with HCV. Cells
were
incubated 18 hours with the virus to allow infection, then washed and
incubated for
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four days. Total RNA was extracted and viral replication was measured by
quantitative RT-PCR.
Typically, 10ø to 105 copies of genomes per well are detected after four days
from infection. To be sure that the measured viral RNA derived from active
replication, a small molecule inhibitor of the viral replicase was included as
a positive
control.
Viral replication was measured on total RNA by quantitative PCR and
expressed as number of HCV copies/350,000 cells. The experiment was performed
in
triplicate wells and values are shown with standard deviations. Fenofibric
acid was
dissolved in DMSO and tested at SOp.M and SOOp,M. Final concentration of DMSO
in
the assay was 0.5%, therefore all the control infections (not-inhibited and
with the
HCV replicase inhibitor) were done in the presence of 0.5% DMSO. The results
are
shown in figure 1, and it is clear that fenofibric acid reduced the
infectivity by up to
90%.
Example 2
A hard gelatine capsule containing 100 mg of fenofibrate may be administered
orally to a 60 Kg adult patient in need thereof for the treatment of HCV
infection.
Such administration may take place twice or three times a~day.
